package com.demo.audiofx;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.view.View;

public class VisualizerView extends View {

	private byte[] mBytes;

	private float[] mPoints;

	private Rect mRect = new Rect();

	private Paint mForePaint = new Paint();

	public VisualizerView(Context context) {
		super(context);
		init();
	}

	private void init() {

		mBytes = null;

		mForePaint.setStrokeWidth(1f);

		mForePaint.setAntiAlias(true);

		mForePaint.setColor(Color.rgb(0, 128, 255));

	}

	public void updateVisualizer(byte[] bytes) {

		mBytes = bytes;

		invalidate();

	}

	@Override
	protected void onDraw(Canvas canvas) {

		super.onDraw(canvas);

		if (mBytes == null) {
			return;
		}

		if (mPoints == null || mPoints.length < mBytes.length * 4) {
			mPoints = new float[mBytes.length * 4];
		}

		mRect.set(0, 0, getWidth(), getHeight());

		for (int i = 0; i < mBytes.length - 1; i++) {

			mPoints[i * 4] = mRect.width() * i / (mBytes.length - 1);
			mPoints[i * 4 + 1] = mRect.height() / 2
					+ ((byte) (mBytes[i] + 128)) * (mRect.height() / 2) / 128;
			mPoints[i * 4 + 2] = mRect.width() * (i + 1) / (mBytes.length - 1);
			mPoints[i * 4 + 3] = mRect.height()
					+ ((byte) (mBytes[i + 1] + 128)) * (mRect.height() / 2)
					/ 128;
		}

		canvas.drawLines(mPoints, mForePaint);

	}

}
